Two SUVs with more similarities, such as the body structure, market segment, starting price, ground shadow size, height, and maximum occupancy, than differences, like the model year, horsepower, and fuel economy. First of all, there is a difference in model years. The is 3 years newer. And finally, the 2013 X3 has a more powerful engine and gets 1.5 mpg less than the 2016 GLC-Class. Among similarities are the body structure, market segment, starting price, ground shadow size, height, and maximum occupancy.